diff --git a/cmd/proc.go b/cmd/proc.go
index df56fb8..0938f45 100644
--- a/cmd/proc.go
+++ b/cmd/proc.go
@@ -90,7 +90,7 @@ var procCmd = &cobra.Command{
 			logrus.Error(err)
 		}
 
-		reg.SaveScenesToTiff(panScenes, mssScenes)
+		reg.OutputL1A(panScenes, mssScenes)
 		producer.CleanScenes(panScenes)
 		producer.CleanScenes(mssScenes)
 
diff --git a/cmd/warp.go b/cmd/warp.go
index a4ca6bb..76ac864 100644
--- a/cmd/warp.go
+++ b/cmd/warp.go
@@ -22,15 +22,15 @@ var (
 
 var cmdWarp = &cobra.Command{
 	Use:   "warp",
-	Short: "transform the input image using rpc",
+	Short: "L1A to L2: transform the input image using rpc",
 	Run: func(cmd *cobra.Command, args []string) {
 		godal.RegisterAll()
 		dem.Dem1KmLT = dem.NewDem1Km(config.GCONFIG.Dem.Dem1Km)
 		warpDEM, _ = filepath.Abs(config.GCONFIG.Dem.Dem1Km)
-		err := producer.Warp(warpIn, warpOut, warpMeta, warpRPC, warpDEM)
+		err := producer.L1AtoL2(warpIn, warpOut, warpMeta, warpRPC, warpDEM)
 		if err != nil {
 			logrus.Error("Generate L2 product failed:", err)
-			os.Exit(10)
+			os.Exit(1)
 		}
 	},
 }
diff --git a/pkg/producer/meta.go b/pkg/producer/meta.go
index 16f3af5..4cb70d1 100644
--- a/pkg/producer/meta.go
+++ b/pkg/producer/meta.go
@@ -2,6 +2,7 @@ package producer
 
 import (
 	"encoding/xml"
+	"math"
 	"os"
 	"path/filepath"
 	"strings"
@@ -58,6 +59,26 @@ type Corners struct {
 	LowerLeft  Location `xml:"LowerLeft"`
 }
 
+func (corners Corners) Extend() (lng1, lat1, lng2, lat2 float64) {
+	lng1 = math.Min(corners.UpperLeft.Longitude, corners.LowerLeft.Longitude)
+	lng1 = math.Min(lng1, corners.UpperRight.Longitude)
+	lng1 = math.Min(lng1, corners.LowerRight.Longitude)
+
+	lat1 = math.Max(corners.UpperLeft.Latitude, corners.LowerLeft.Latitude)
+	lat1 = math.Max(lat1, corners.UpperRight.Latitude)
+	lat1 = math.Max(lat1, corners.LowerRight.Latitude)
+
+	lng2 = math.Max(corners.UpperLeft.Longitude, corners.LowerLeft.Longitude)
+	lng2 = math.Max(lng2, corners.UpperRight.Longitude)
+	lng2 = math.Max(lng2, corners.LowerRight.Longitude)
+
+	lat2 = math.Min(corners.UpperLeft.Latitude, corners.LowerLeft.Latitude)
+	lat2 = math.Min(lat2, corners.UpperRight.Latitude)
+	lat2 = math.Min(lat2, corners.LowerRight.Latitude)
+
+	return
+}
+
 func (r *Registrator) makeProductMeta(scene *Scene) *ProductMeta {
 	meta := &ProductMeta{
 		Satellite:      "SJY01",
@@ -89,7 +110,7 @@ func (r *Registrator) makeProductMeta(scene *Scene) *ProductMeta {
 	return meta
 }
 
-func (r *Registrator) writeProductMeta(productMeta *ProductMeta, filename string) error {
+func writeProductMeta(productMeta *ProductMeta, filename string) error {
 	output, err := xml.MarshalIndent(productMeta, "", "    ")
 	if err != nil {
 		return err
diff --git a/pkg/producer/scenes.go b/pkg/producer/scenes.go
index 451c785..cf362e6 100644
--- a/pkg/producer/scenes.go
+++ b/pkg/producer/scenes.go
@@ -159,7 +159,7 @@ func (r *Registrator) SubScenes() (panScenes []*Scene, mssScenes []*Scene, err e
 	return panScenes, mssScenes, err
 }
 
-func (r *Registrator) SaveScenesToTiff(panScenes []*Scene, mssScenes []*Scene) error {
+func (r *Registrator) OutputL1A(panScenes []*Scene, mssScenes []*Scene) error {
 	var fc geojson.FeatureCollection
 	for i, scene := range panScenes {
 		dir := filepath.Join(r.Params.OutputDir, scene.SceneIndex, "PAN")
@@ -182,7 +182,7 @@ func (r *Registrator) SaveScenesToTiff(panScenes []*Scene, mssScenes []*Scene) e
 
 		scene.Meta.DataSize = sizeOfFile(scene.Tiff)
 		metaFile := strings.Replace(scene.Tiff, ".tiff", ".meta.xml", 1)
-		r.writeProductMeta(scene.Meta, metaFile)
+		writeProductMeta(scene.Meta, metaFile)
 		jpg := strings.Replace(scene.Tiff, ".tiff", ".jpg", 1)
 		GTiffToJPG(scene.Tiff, jpg, "PAN", false)
 		r.report.Scenes = append(r.report.Scenes, ReportScene{
@@ -233,7 +233,7 @@ func (r *Registrator) SaveScenesToTiff(panScenes []*Scene, mssScenes []*Scene) e
 
 		scene.Meta.DataSize = sizeOfFile(scene.Tiff)
 		metaFile := strings.Replace(scene.Tiff, ".tiff", ".meta.xml", 1)
-		r.writeProductMeta(scene.Meta, metaFile)
+		writeProductMeta(scene.Meta, metaFile)
 		jpg := strings.Replace(scene.Tiff, ".tiff", ".jpg", 1)
 		GTiffToJPG(scene.Tiff, jpg, "MSS", false)
 		r.report.Scenes = append(r.report.Scenes, ReportScene{
diff --git a/pkg/producer/warp.go b/pkg/producer/warp.go
index b607b5d..3ac46a5 100644
--- a/pkg/producer/warp.go
+++ b/pkg/producer/warp.go
@@ -1,13 +1,13 @@
 package producer
 
 import (
-	"math"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
 
+	"github.com/airbusgeo/godal"
 	log "github.com/sirupsen/logrus"
 	"starwiz.cn/sjy01/image-proc/pkg/dem"
 )
@@ -15,7 +15,7 @@ import (
 // gdalwarp -rpc -to "RPC_HEIGHT=2375" in.tif out.tif
 // gdalwarp -rpc -to "RPC_DEM=/path/to/dem/gdlebm.tif" in.tif out.tif
 
-func Warp(in, out, meta, rpb, demtif string) error {
+func L1AtoL2(in, out, meta, rpb, demtif string) error {
 	meta, _ = filepath.Abs(meta)
 	m, err := ParseProductMeta(meta)
 	if err != nil {
@@ -27,7 +27,7 @@ func Warp(in, out, meta, rpb, demtif string) error {
 
 	log.Infof("Warping %s to %s", in, out)
 	minEv, maxEv := dem.Dem1KmLT.MinMaxElevationInRect(
-		computeExtend(&m.Corners),
+		m.Corners.Extend(),
 	)
 	log.Infof("DEM min/max elevation: %f/%f", minEv, maxEv)
 	var cmd *exec.Cmd
@@ -49,27 +49,106 @@ func Warp(in, out, meta, rpb, demtif string) error {
 	if strings.Contains(m.ProductID, "PAN") {
 		sensor = "PAN"
 	}
+
+	corners, err := computeBound(out)
+	if err != nil {
+		return err
+	}
+
+	id := filepath.Base(out)
+	id = strings.Replace(id, ".tiff", "", 1)
+	m.ProductID = id
+	m.ProductLevel = "L2"
+	m.Corners = *corners
+	xmlfile := filepath.Join(dir, id+".meta.xml")
+	writeProductMeta(m, xmlfile)
+
 	GTiffToJPG(out, strings.Replace(out, ".tiff", ".jpg", 1), sensor, false)
 
 	return nil
 }
 
-func computeExtend(corners *Corners) (lng1, lat1, lng2, lat2 float64) {
-	lng1 = math.Min(corners.UpperLeft.Longitude, corners.LowerLeft.Longitude)
-	lng1 = math.Min(lng1, corners.UpperRight.Longitude)
-	lng1 = math.Min(lng1, corners.LowerRight.Longitude)
+func computeBound(tif string) (*Corners, error) {
+	ds, err := godal.Open(tif)
+	if err != nil {
+		log.Printf("Error opening TIFF file %s: %v", tif, err)
+		return nil, err
+	}
+	defer ds.Close()
 
-	lat1 = math.Max(corners.UpperLeft.Latitude, corners.LowerLeft.Latitude)
-	lat1 = math.Max(lat1, corners.UpperRight.Latitude)
-	lat1 = math.Max(lat1, corners.LowerRight.Latitude)
+	geotransform, err := ds.GeoTransform()
+	if err != nil {
+		return nil, err
+	}
 
-	lng2 = math.Max(corners.UpperLeft.Longitude, corners.LowerLeft.Longitude)
-	lng2 = math.Max(lng2, corners.UpperRight.Longitude)
-	lng2 = math.Max(lng2, corners.LowerRight.Longitude)
+	// Xp = padfTransform[0] + P*padfTransform[1] + L*padfTransform[2];
+	// Yp = padfTransform[3] + P*padfTransform[4] + L*padfTransform[5];
 
-	lat2 = math.Min(corners.UpperLeft.Latitude, corners.LowerLeft.Latitude)
-	lat2 = math.Min(lat2, corners.UpperRight.Latitude)
-	lat2 = math.Min(lat2, corners.LowerRight.Latitude)
+	structure := ds.Structure()
+	xmin := geotransform[0]
+	ymax := geotransform[3]
+	xmax := xmin + geotransform[1]*float64(structure.SizeX)
+	ymin := ymax + geotransform[5]*float64(structure.SizeY)
+	log.Infof("extend: %f,%f,%f,%f", xmin, ymin, xmax, ymax)
+	log.Infof("geotransform: %v", geotransform)
 
-	return
+	band := ds.Bands()[0]
+	width := structure.SizeX
+	height := structure.SizeY
+	data := make([]uint16, width*height)
+	err = band.Read(0, 0, data, width, height)
+	if err != nil {
+		return nil, err
+	}
+
+	nodata, _ := band.NoData()
+
+	index1 := 0
+	for x := 0; x < width; x++ {
+		value := data[0*width+x]
+		if value != uint16(nodata) {
+			index1 = x
+			break
+		}
+	}
+
+	index2 := 0
+	for x := 0; x < width; x++ {
+		value := data[(height-1)*width+x]
+		if value != uint16(nodata) {
+			index2 = x
+			break
+		}
+	}
+
+	index3 := 0
+	for y := 0; y < height; y++ {
+		value := data[y*width]
+		if value != uint16(nodata) {
+			index3 = y
+			break
+		}
+	}
+
+	index4 := 0
+	for y := 0; y < height; y++ {
+		value := data[y*width+width-1]
+		if value != uint16(nodata) {
+			index4 = y
+			break
+		}
+	}
+
+	var corners Corners
+
+	corners.UpperLeft.Longitude = xmin + float64(index1)*geotransform[1]
+	corners.UpperLeft.Latitude = ymax
+	corners.UpperRight.Longitude = xmax
+	corners.UpperRight.Latitude = ymax + float64(index4)*geotransform[5]
+	corners.LowerLeft.Longitude = xmin
+	corners.LowerLeft.Latitude = ymax + float64(index3)*geotransform[5]
+	corners.LowerRight.Longitude = xmin + float64(index2)*geotransform[1]
+	corners.LowerRight.Latitude = ymin
+
+	return &corners, nil
 }